Define a grouping for source files in IDE project generation.

source_group(<name> [FILES <src>...] [REGULAR_EXPRESSION <regex>])

Defines a group into which sources will be placed in project files. This is intended to set up file tabs in Visual Studio. The options are:

Any source file specified explicitly will be placed in group <name>. Relative paths are interpreted with respect to the current source directory.
Any source file whose name matches the regular expression will be placed in group <name>.

If a source file matches multiple groups, the last group that explicitly lists the file with FILES will be favored, if any. If no group explicitly lists the file, the last group whose regular expression matches the file will be favored.

The <name> of the group may contain backslashes to specify subgroups:

source_group(outer\\inner ...)

For backwards compatibility, the short-hand signature

source_group(<name> <regex>)

is equivalent to

source_group(<name> REGULAR_EXPRESSION <regex>)